Implement the new driver method 'reg_user_mr_dmabuf'. Utilize the core functions to import dma-buf based memory region and update the mappings.

Add code to handle dma-buf related page fault.

Signed-off-by: Jianxin Xiong jianxin.xiong@intel.com Reviewed-by: Sean Hefty sean.hefty@intel.com Acked-by: Michael J. Ruhl michael.j.ruhl@intel.com Acked-by: Christian Koenig christian.koenig@amd.com --- drivers/infiniband/hw/mlx5/main.c | 2 + drivers/infiniband/hw/mlx5/mlx5_ib.h | 5 ++ drivers/infiniband/hw/mlx5/mr.c | 119 +++++++++++++++++++++++++++++++++++ drivers/infiniband/hw/mlx5/odp.c | 42 +++++++++++++ 4 files changed, 168 insertions(+)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c index 89e04ca..ec4ad2f 100644 --- a/drivers/infiniband/hw/mlx5/main.c +++ b/drivers/infiniband/hw/mlx5/main.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB /* * Copyright (c) 2013-2020, Mellanox Technologies inc. All rights reserved. + * Copyright (c) 2020, Intel Corporation. All rights reserved. */

#include <linux/debugfs.h> @@ -4060,6 +4061,7 @@ static int mlx5_ib_enable_driver(struct ib_device *dev) .query_srq = mlx5_ib_query_srq, .query_ucontext = mlx5_ib_query_ucontext, .reg_user_mr = mlx5_ib_reg_user_mr, + .reg_user_mr_dmabuf = mlx5_ib_reg_user_mr_dmabuf, .req_notify_cq = mlx5_ib_arm_cq, .rereg_user_mr = mlx5_ib_rereg_user_mr, .resize_cq = mlx5_ib_resize_cq, diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h index b1f2b34..65fcc18 100644 --- a/drivers/infiniband/hw/mlx5/mlx5_ib.h +++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h @@ -1,6 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */ /* * Copyright (c) 2013-2020, Mellanox Technologies inc. All rights reserved. + * Copyright (c) 2020, Intel Corporation. All rights reserved. */

#ifndef MLX5_IB_H @@ -1174,6 +1175,10 @@ int mlx5_ib_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr, struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, u64 virt_addr, int access_flags, struct ib_udata *udata); +struct ib_mr *mlx5_ib_reg_user_mr_dmabuf(struct ib_pd *pd, u64 start, + u64 length, u64 virt_addr, + int dmabuf_fd, int access_flags, + struct ib_udata *udata); int mlx5_ib_advise_mr(struct ib_pd *pd, enum ib_uverbs_advise_mr_advice advice, u32 flags, diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c index b261797..24750f1 100644 --- a/drivers/infiniband/hw/mlx5/mr.c +++ b/drivers/infiniband/hw/mlx5/mr.c @@ -1,5 +1,6 @@ /* * Copyright (c) 2013-2015, Mellanox Technologies. All rights reserved. + * Copyright (c) 2020, Intel Corporation. All rights reserved. * * This software is available to you under a choice of one of two * licenses. You may choose to be licensed under the terms of the GNU @@ -1462,6 +1463,124 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, return ERR_PTR(err); }

+static int mlx5_ib_umem_dmabuf_xlt_init(struct ib_umem *umem, void *context) +{ + struct mlx5_ib_mr *mr = context; + int flags = MLX5_IB_UPD_XLT_ENABLE; + + if (!mr) + return -EINVAL; + + return mlx5_ib_update_xlt(mr, 0, mr->npages, PAGE_SHIFT, flags); +} + +static int mlx5_ib_umem_dmabuf_xlt_update(struct ib_umem *umem, void *context) +{ + struct mlx5_ib_mr *mr = context; + int flags = MLX5_IB_UPD_XLT_ATOMIC; + + if (!mr) + return -EINVAL; + + return mlx5_ib_update_xlt(mr, 0, mr->npages, PAGE_SHIFT, flags); +} + +static int mlx5_ib_umem_dmabuf_xlt_invalidate(struct ib_umem *umem, void *context) +{ + struct mlx5_ib_mr *mr = context; + int flags = MLX5_IB_UPD_XLT_ZAP | MLX5_IB_UPD_XLT_ATOMIC; + + if (!mr) + return -EINVAL; + + return mlx5_ib_update_xlt(mr, 0, mr->npages, PAGE_SHIFT, flags); +} + +static struct ib_umem_dmabuf_ops mlx5_ib_umem_dmabuf_ops = { + .init = mlx5_ib_umem_dmabuf_xlt_init, + .update = mlx5_ib_umem_dmabuf_xlt_update, + .invalidate = mlx5_ib_umem_dmabuf_xlt_invalidate, +}; + +struct ib_mr *mlx5_ib_reg_user_mr_dmabuf(struct ib_pd *pd, u64 start, + u64 length, u64 virt_addr, + int dmabuf_fd, int access_flags, + struct ib_udata *udata) +{ + struct mlx5_ib_dev *dev = to_mdev(pd->device); + struct mlx5_ib_mr *mr = NULL; + struct ib_umem *umem; + int page_shift; + int npages; + int ncont; + int order; + int err; + + if (!IS_ENABLED(CONFIG_INFINIBAND_USER_MEM)) + return ERR_PTR(-EOPNOTSUPP); + + mlx5_ib_dbg(dev, + "start 0x%llx, virt_addr 0x%llx, length 0x%llx, fd %d, access_flags 0x%x\n", + start, virt_addr, length, dmabuf_fd, access_flags); + + if (!mlx5_ib_can_load_pas_with_umr(dev, length)) + return ERR_PTR(-EINVAL); + + umem = ib_umem_dmabuf_get(&dev->ib_dev, start, length, dmabuf_fd, + access_flags, &mlx5_ib_umem_dmabuf_ops); + if (IS_ERR(umem)) { + mlx5_ib_dbg(dev, "umem get failed (%ld)\n", PTR_ERR(umem)); + return ERR_PTR(PTR_ERR(umem)); + } + + npages = ib_umem_num_pages(umem); + if (!npages) { + mlx5_ib_warn(dev, "avoid zero region\n"); + ib_umem_release(umem); + return ERR_PTR(-EINVAL); + } + + page_shift = PAGE_SHIFT; + ncont = npages; + order = ilog2(roundup_pow_of_two(ncont)); + + mlx5_ib_dbg(dev, "npages %d, ncont %d, order %d, page_shift %d\n", + npages, ncont, order, page_shift); + + mr = alloc_mr_from_cache(pd, umem, virt_addr, length, ncont, + page_shift, order, access_flags); + if (IS_ERR(mr)) + mr = NULL; + + if (!mr) { + mutex_lock(&dev->slow_path_mutex); + mr = reg_create(NULL, pd, virt_addr, length, umem, ncont, + page_shift, access_flags, false); + mutex_unlock(&dev->slow_path_mutex); + } + + if (IS_ERR(mr)) { + err = PTR_ERR(mr); + goto error; + } + + mlx5_ib_dbg(dev, "mkey 0x%x\n", mr->mmkey.key); + + mr->umem = umem; + set_mr_fields(dev, mr, npages, length, access_flags); + + err = ib_umem_dmabuf_init_mapping(umem, mr); + if (err) { + dereg_mr(dev, mr); + return ERR_PTR(err); + } + + return &mr->ibmr; +error: + ib_umem_release(umem); + return ERR_PTR(err); +} + /** * mlx5_mr_cache_invalidate - Fence all DMA on the MR * @mr: The MR to fence diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c index 5c853ec..16e2e51 100644 --- a/drivers/infiniband/hw/mlx5/odp.c +++ b/drivers/infiniband/hw/mlx5/odp.c @@ -801,6 +801,44 @@ static int pagefault_implicit_mr(struct mlx5_ib_mr *imr, * Returns: * -EFAULT: The io_virt->bcnt is not within the MR, it covers pages that are * not accessible, or the MR is no longer valid. + * -EAGAIN: The operation should be retried + * + * >0: Number of pages mapped + */ +static int pagefault_dmabuf_mr(struct mlx5_ib_mr *mr, struct ib_umem *umem, + u64 io_virt, size_t bcnt, u32 *bytes_mapped, + u32 flags) +{ + u64 user_va; + u64 end; + int npages; + + if (unlikely(io_virt < mr->mmkey.iova)) + return -EFAULT; + if (check_add_overflow(io_virt - mr->mmkey.iova, + (u64)umem->address, &user_va)) + return -EFAULT; + + /* Overflow has alreddy been checked at the umem creation time */ + end = umem->address + umem->length; + if (unlikely(user_va >= end || end - user_va < bcnt)) + return -EFAULT; + + if (!ib_umem_dmabuf_mapping_ready(umem)) + return -EAGAIN; + + if (bytes_mapped) + *bytes_mapped += bcnt; + + npages = (ALIGN(user_va + bcnt, PAGE_SIZE) - + ALIGN_DOWN(user_va, PAGE_SIZE)) >> PAGE_SHIFT; + return npages; +} + +/* + * Returns: + * -EFAULT: The io_virt->bcnt is not within the MR, it covers pages that are + * not accessible, or the MR is no longer valid. * -EAGAIN/-ENOMEM: The operation should be retried * * -EINVAL/others: General internal malfunction @@ -811,6 +849,10 @@ static int pagefault_mr(struct mlx5_ib_mr *mr, u64 io_virt, size_t bcnt, { struct ib_umem_odp *odp = to_ib_umem_odp(mr->umem);

+ if (mr->umem->is_dmabuf) + return pagefault_dmabuf_mr(mr, mr->umem, io_virt, bcnt, + bytes_mapped, flags); + lockdep_assert_held(&mr->dev->odp_srcu); if (unlikely(io_virt < mr->mmkey.iova)) return -EFAULT;